Milk bottle cap and method of making the same



H. w. MARTIN 2,221,197

Nov. 12, 1940. .Y

MILK BOTTLE CAP AND METHOD O F MAKING THE SAME Filed May 7, 193e VII '/i '7 if Patented Nov. 12, 1940 .UNHTED STATE rer orrics lVIILK BOTTLECAP AND METHOD OF MAKING THE SAME Ware Application May 7, 1936, SerialNo. l78,361

9 Claims.

This invention relatesto milk bottle caps of the so-called cover-alltype in which the outer face of the pouring lip of the bottle is coveredby the cap. A well known cap of this type is disclosed in the BaumPatent No. 1,668,349. This invention has for an object to improve theconstruction of such a cap, whereby the skirt which encloses the topportionof the bottle is rendered more resistant to flaring under theconditions of use which include subjection of the top portion of thebottle to water and ice and to pressure while subjected to moistureconditions.

In caps of this type, as previously constructed, the skirt has been ofnon-uniform width throughout, the lower edge being more or lessirregular, depending somewhat on the uniformity or lack of uniformity invarious directions of the paper of which the caps are formed and on thearrangement of the overlapping layers of the paper. In accordance withthe present invention, this skirt is rendered of substantially uniformlength throughout and is so treated in the manufacture that it presentsa dense horn-like structure more resistant to the entrance of moisturethan has been previously the case.

A further object of the present invention is to effect a reinforcementof the cap which materially increases its strength.

A still further object is to provide a construction which, when the capsare stacked, as when they are positioned in the supply reservoir of abottle feeding and capping machine, prevents any tendency for pressurebetween the caps to cause aring of their skirt portions and whichinsures easy feed of the caps one by one from the lower end of thestack, as desired, without the possibility of the caps catching on eachother.

A still further object is to improve the general appearance of the cap.

For more complete understanding of this invention, reference may be hadto the accompanying drawing in which Figure 1 is a perspective view insection of the main portion of a cap constructed in accordance with thisinvention.

Figures 2 and 3 are fragmentary sections to a larger scale throughdifferent portions of the bottle-lip-enolosing part of the cap.

Figures 4 to 7 inclusive are fragmentary diagrammatic section viewsshowing successive steps in the formation of the main part of the cap.

Figure 8 is a View, partly in side elevation and partly in section ofthree caps in stacked relation. r

The cap is preferably formed up from paper of the desired thicknesswhich has previously been subjected to treatment such as described invthe Baum Patent No. 1,668,349 previously mentioned, being preferablymoistened and then v5 passed through a bath of hot wax, such as parafn,with the addition of a small amount of hardening wax, such as carnaubaor montan wax, after which the paper blanks are allo-wed to stand inclosed containers to temper so as to give the l0 moisture time topenetrate through the fibers' and to reduce the paper to a temperedmoldable condition. The circular paper blank.| (see Figure 4) is thensubjected to a molding operation K as between dies, the paperfirst beingengaged 15 over its central disc portion between the die portions 2 and3. Then the annular die member 6 is caused 'to move into the position'shown in Figure 5, forming the upstanding inner wall 1 of the pouringlip housing of the cap, this die 20 portion 'l cooperating with a matingdie member 8 to form the top wallof the pouring liphousing. The marginalportion of the cap blank is then pressed downwardly, as by the annulardie member "Las shown in Figure 6, to form a depending skirt lZ whichprojects downwardly some distance below the inner wall 1 and insubstantially parallel relation thereto and concentric therewith. Thedie members, particularly those which form the skirt portion, subjectthe treated ypaper stock to heavy pressure such as to produce thetranslucent horn-like structure described in the Baum patent, to whichreference has heretofore been made. The process of forming the capprevious to this invention has been allowed.l to stop here, as describedin the Baum patent, and `thel lower edge' of the skirt portion l2 hasalwaysbeen more or less irregular.

In accordance with the present invention, this lack of uniformity isovercome by applying pressure against the edge of this skirt, compactingvand more closely interfelting the material thereof, and condensing thisedge so that italso is formed into a dense horn-like surface structure.As shown, this is done `by the annular die'member i3 which moves betweenthe-members 8 and Ill and narrows the'skirt from the width shown inFigure 6 to that shown'in Figure 7. This narrowing of the skirt isproduced while it is supported on opposite faces yby the die portions 6and it Which produce heavy pressure thereon and prevent increase inthickness of the skirt which remains throughout the processsubstantially that of the single layer of the paper blank. The endwisepressure thus acts on the free edge positioned opposite to the ribs M.

of the skirt which is the free edge of the blank. This is supportedagainst folding up or bending while the edge pressure is exerted, sothat this edge is reduced to the desired horn-like structure, surfacesealed against the entrance of moisture. Where this edge compacting isnot employed, the relatively rough edge of the skirt has been less ableto resist the entrance of moisture into the material of the cap and theentrance of such moisture promotes flaring of the cap skirt later on,permitting it to spring away somewhat from the bottle and impairing theholding ability of the cap thereon. While the treatment of the sidewalls of the skirt portion between the dies under heavy pressure hasbeen found very effective to prevent flaring, this further cornpactingof the edge of the skirt further increases the ability of the cap towithstand daring under the severe conditions of icing and pressure towhich these caps are subjected in service.

Besides condensing this end edge and bringing it into a common plane,advantage may be taken of this pressure, in accordance with the presentinvention, for producing further desirable improvements in the capstructure. Thus the die member 8 may be provided with substantiallyradially arranged depressions in its lower face so that the endwisepressure of the skirt portions causes the paper stock to be driven upinto these depressions, producing radial reinforcing ribs of solidcross-section across the top wall of the pouring lip housing, as shownat I4 in Figure l. The upperface of the die member 6 is preferably plainso as to form the lower face of the upper wall of this housing withoutdepressions These ribs, being of solid cross section, are of materiallygreater strength than those shown in the. Baum patent and previousconstructions wherein the ribs are merely corrugations inthe capmaterial so that the lower face of the upper wall of the housing hasdepressions positioned opposite to each of the ribs on the top face.Figure 2 shows a section taken through the pouring lip housing betweenthe stiffening ribs while Figure 3 is a similar View showing a sectiontaken through one of the ribs.

A further improvement which materially strengthens the cap may also beproduced by providing the upper face of the die member 6 with an annulardepression or groove, as at I5, adjacent to its outer edge so that, whenthe paper stool-z is condensed by edgewise pressure exerted on theskirt, this depression is filled forming a thickened annular reinforcingfor the cap adjacent to the outer or skirt wall portion I2.

It is likewise preferable to provide an annular channel around the topedge of the skirt portion and, as shown, this is provided within the diemember l0, as at 2i). This grooved portion is also filled with the paperstock by the molding pressure exerted on the lower end of the skirt,thus forming an annular upstanding rib 2! about the outer margin of thepouring lip housing as an upward extension of the skirt i2 above the topof the pouring lip housing. The top of this rib or marginal bead is atleast as high as adjacent portions of the radial ribs i4 which terminateat the inner face thereof so that the outer ends of the radial ribs arenot engaged by the superposed cap in the stack. Preferably, the dies areso formed and the size of the blank is so proportioned that in the finalmolded condition of the cap skirt shown in Figure 7 the outer edge ofthe skirt i2 is brought to such a position that when the caps arestacked the engagement between them is at least mainly in alinement withthe inner wall 1, thus relieving the outer wall of the skirt from anysubstantial wedging pressure tending to cause spreading. Thus, when thecaps are stacked, as shown in Figure 8, it is an easy matter to feed outthe lowest cap of the stack, there being little, if any, tendency forthe cap thereabove to catch thereon and offer obstruction to such freeremoval.

Besides greatly improving the cap from the standpoint of ease ofhandling and effectiveness in resisting the stresses of use, thistreatment substantially improves the appearance of the cap, particularlywhere the outer parts of the stock of which the cap is made are colored.This treatment deepens the color at the lower edge of the skirt and addsgreatly to the ornamental appearance of the cap, both when it is on thebottle and when it is associated with other caps in a stack, as receivedfrom the manufacturer for application to a bottle filling and-cappingmachine.

After the formation of the caps, as hereinbefore described, they may beprovided with reinforcing disks, such as are shown at 25 in Figure 6, asis well known in the art, such disks serving to reinforce and stiifenthe central depressed portion of the caps which enter into the mouths ofthe bottles.

From the foregoing description of the cap and a method of making thesame, it should be evident to those skilled in the art that variouschanges and modifications may be made without f departing from thespirit or scope of this invention as dened by the appended claims.

I claim:

1. A milk bottle cap having a depressed central portion to enter themouth of a bottle and an annular pouring lip housing of generallychannel shape in cross-section outwardly of said central portion, saidhousing having inner and outer substantially parallel walls and a topwall bridging said parallel walls, said top wall having thickenedsubstantially radially arranged ribs on its upper face, the lower faceof said top wall being substantially devoid of depressions opposite thesaid ribs, said top wall being substantially thicker adjacent to itssaid outer wall than adjacent to said inner wall and presenting anupstanding marginal bead on its upper face outwardly of said ribsadapted to register with the lower edge of the outer wall of asuperimposed cap in a stack.

2. A rigid molded paper article formed up from a blank of waxed paper,said article having a central disc portion and a marginal portion ofgenerally inverted U-shape cross section extending upwardly therefrom toform an inner vertical flange and an outer depending skirt having abottom free edge formed by the free edge of the blank, said skirtcomprising folded layers of said paper, interfelted and compressedtransversely to a dense water-resistant horn-like condition throughoutthe length thereof and being of a thickness corresponding to a singlelayer of said blank, said free edge being interfelted and compressedaxially to a dense water-resistant horn-like surface capable ofresisting penetration of moisture into the fibers from the exposed edgethereof and forming a substantially straight edge devoid ofirregularities which would interfere with the feeding of the individualarticles from a stack thereof.

Cil

3. A rigid molded paper article formedv up from a blank of waxed paper,said article having a central disc portion and a marginal portion ofgenerally inverted U-shape cross section extend- 5- ing upwardlytherefrom to form an inner vertical flange, a top portion and an outerdepending skirt, said skirt comprising folded layers of saidl paperinterfelted and compressed trans- I versely to a dense water-resistanthorn-like condition throughout the length thereof, the free edge of saidskirt being interfelted and compressed axially to a densewater-resistant hornlike surface capable of resisting penetration of`moisture into the fibers from the exposed edge thereof and forming asubstantially smooth, straight bottom edge and a raised marginal beadmolded on said top portion in alinement with and forming an upwardcontinuation of said skirt, said bead having a smooth top surfaceadapted to engage and support the skirt of a similar article stackedthereon, the smooth bottom edge of said skirt and the smooth top surfaceof said bead cooperating to permit feeding of the individual articlesfrom a stack without injury to or deformation of the respective skirts.

4. A rigid milk bottle cap formed up from a blank of waxed paper, saidcap having a central bore closing portion and pouring lip housingsubstantially U-shape in cross section with an inner vertical flange andan outer depending skirt having an outer free edge formed by the freeedge of the blank, said skirt comprising folded layers of said paper,interfelted and compressed transversely to a dense water-resistanthorn-like condition throughout the length thereof and being of athickness corresponding to a single layer of said blank, said free edgebeing interfelted and compressed axially to a dense water-resistanthorn-like surface capable of resisting penetration of moisture into thebers from the exposed edge thereof and forming a substantially straightedge devoid of irregularities which would interfere with the feeding ofthe individual articles from a stack thereof.

5. A rigid milk bottle cap formed up from a blank of waxed paper, saidcap having a central bore closing portion and pouring lip housingsubstantially U-shape in cross section with an inner vertical flange, atop portion and an outer depending skirt, said skirt comprising foldedlayers of said paper interfelted and compressed transversely to a densewater-resistant horn-like condition throughout the length thereof, thefree edge of said skirt being interfelted and compressed axially to adense water-resistant hornlike surface capable of resisting penetrationof moisture into the fibers from the exposed edge thereof and forming asubstantially smooth, straight edge, and a raised marginal bead moldedon said top portion in alinement with and forming an upward continuationof said skirt, said bead having a smooth top surface adapted to engageand support the skirt of a similar article stacked thereon, the smoothbottom edge of said skirt and the smooth top surface of said beadcooperating to permit feeding of the individual articles from a stackwithout injury to or deformation of the respective skirts.

6. A rigid milk bottle cap formed up from a blank of waxed paper, saidcap having a central bore closing portion and a pouring lip housingsubstantially U-shape in cross section with an inner vertical flange, atop portion and an outer depending skirt, said skirt comprising foldedlayers of said paper interfelted and compressed transversely to a densewater-resistant horn-like condition throughout the length thereof, thefreev edge of said skirt being interfelted and compressed axially to adense Water-resistant hornlike surface capable of -resisting penetrationof 5 moisture into the fibers from the exposed edge thereof and forminga substantially smooth, straight edge, raised transverse ribs thickerthan the paper of said blank molded on said top portion and a raisedmarginal beadvmolded on said 10 top portion in alinement -with andforming an upward continuation of said skirt, said bead having a smoothtop surface adapted to engage and support the skirt of a similar articlestacked thereon, the smooth bottom edge of said skirt 15 and the smoothtop surface of said bead cooperating to permit feeding of the individualarticles from a stack without injury to or deformation of the respectiveskirts.

7. The method of making a rigid molded paper 20 article from a blank ofwaxed paper which comprises die-forming said article into the shape of acentral disc portion and a marginal portion of generally invertedU-shaped cross section extending upwardly therefrom to form an inner 25vertical flange and an outer depending skirt having folded layers ofsaid paper and having'a bottom free edge formed by the free edge of theblank, subjecting said skirt to a pressure sufficient to interfelt andcompact the folded layers 30 into a substantially homogeneousl rigidhorn-like structure of substantially uniform thickness correspondinggenerally to the thickness of a single layer of said blank and, whilesaid skirt is held under transverse pressure, applying axial pres- 35sure to the free edge thereof sufficient to interfelt and compact thefree edge into a dense water-resistant horn-like condition, whereby saidfree edge becomes capable of resisting penetration of moisture into thefibers from the ex- 40 posed surface thereof.

8. The method of making a rigid molded paper article from a blank ofwaxed paper which cornprises die-forming said article into the shape ofa central disc portion and a marginal portion 45 of generally invertedU-shaped cross section extending upwardly therefrom to form an innervertical flange, a top portion andan outer depending skirt having foldedlayers of said paper, subjecting said skirt' to a pressure sucient to550 interfelt and compact the folded layers into a substantiallyhomogeneous rigid horn-like structure of substantially uniformthickness, and while said skirt is held under transverse pressure,applying axial pressure to the free edge thereof sufficient to interfeltand compact the free edge into a dense Water-resistant horn-likecondition, whereby said free edge becomes capable of resistingpenetration of moisture-into the fibers from the exposed surfacethereof, and uti- 60 lizing said axial pressure to cause the bers ofsaid skirt to ilow upwardly and form a raised annular bead on said topportion in alinement with said skirt, the upper surface. of said bead.and bottom edge of said skirt being caused to 65 have substantiallystraight surfaces adapted to facilitate the feeding of the individualarticles from a stack thereof without causing injury to or deformationof the respective skirts.

9. The method of making a rigid molded paper 70 article from a blank ofwaxed paper which comprises die-forming said article into the shape of acentral disc portion and a marginal portion of generally inverted`Ushaped cross section extending upwardly therefrom to form an inner`1li lizing said axial pressure on said skirt to cause the bers to flowupwardly to form a raised marginal bead on said top portion in alinementwith said skirt and to form on said top portion raised transverse ribssubstantially thicker than the paper of said blank, said skirt and beadbeing compact axially to form substantially straight upper and lowersurfaces adapted to facilitate the feeding of the individual articlesfrom a stack thereof without causing destruction or injury to 10 therespective skirts.

HAROLD W. MARTIN.

